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If extended highway driving isn't a concern, which transmission would you choose?

  • TH-350C

    Votes: 1 50.0%
  • Th-700R4

    Votes: 1 50.0%

  • Total voters
    2
  • Poll closed .
1 - 5 of 5 Posts

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Gran Turismologist
Joined
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35 Posts
Discussion Starter #1
I am beginning to plan for a major overhaul to "The Argo", my trusty 1996 F-150. I am interested in making it a 4x4 (these trucks are easy to convert), with a 6.2L diesel. My question is about my transmission choices. I do not use this truck anymore as a primary vehicle. It served in that capacity for a very long time, and I enjoy driving it, but the mileage it gets makes it too expensive to operate regularly. The purpose of swapping in a diesel engine is to gain efficiency and the ability to run on homemade fuel (eventually). I want to put a 6.2L diesel in it, and I want to make it as efficient as I can without compromising it's abilities.

The truck is currently powered by the factory 300ci straight six, and has 3.73 gears, and a cast iron NP-435 4 speed manual transmission. The 4 speed can be converted with a Novak adapter and a new output shaft to run a transfer case, and it can be adapted to a GM clutch housing, so running the 4 speed with the 6.2L is a possibility. If this plan fails, however, I intend to go with a GM automatic transmission.

The truck will be fitted with 31 inch tires, and I intend to keep the 3.73 gears, because I tow and haul significant loads frequently with this truck. If I need to go automatic, I do not want to use a TH-400. While it is bullet proof, it is a power hog, and I am concerned that it will cost me mileage and make the 6.2L feel more sluggish than the six it will replace (even though their dyno sheets are virtually a carbon copy of each other).

What I don't know however, it whether the TH-350C is stronger than the TH-700R4. If it is, I want to use it, because this truck doesn't see much highway driving unless I am towing something or hauling something heavy, in which case I don't use overdrive anyway. If they are equal strength, then I'll go with the 700 because even if I won't use the overdrive all the time, I see no reason not to have it if it doesn't cost me strength.

I want to stay with a manual, but if adapting it will cost too much, I will go automatic. So what is your choice? If extended highway speeds are not a concern, would you go 700R4, or 350C? (Note, not just a 350, because I want a lockup converter!)
 

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Gran Turismologist
Joined
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35 Posts
Discussion Starter #2
Oh, FYI...

Since I am looking for your opinions, I will only watch this thread unless you have a specific question, because I do not want to influence the results one way or the other.
 

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Gone Fishin...
Joined
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3,099 Posts
Depends on the year. A 1987 and earlier 700R4 is a twig compared to the newer 700R4s. But, all things being equal, i'd say they are about even from the factory. The key point is, the TH350 can be built far more cheaply then the 700R4.

If you're mainly going to tow with the truck, pick up the TH350 and upgrade the converter as well as add a shift kit. If not, go with the 700R4.
 

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496 Cubic Inches
Joined
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245 Posts
Yea I agree with Robert. Im no big fan of either trans to be honest. Ive had a few Th400's and there is no beating them when built properly. The 700R4 is just an OD Th350 and both have weak spots. There is a reason they put the TH400 behind the 6.2L.

You can try the SM465 but I dont like the clutch on those nor the ratios. Read up on it here..... http://www.novak-adapt.com/knowledge/sm465.htm

If it were me and you wanted to keep it Ford go BBF 460 and a C6 for auto. If you must have the 6.2 then go 465 manual or go TH400. I wouldnt even try the TH350 because you know you want to play with the power (Not that these had any N/A). The TH350 are decent when built right but are expensive to get to that point. Also better for cars and lighter weight trucks.

Just my opinion though.
 
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